[meteorite-list] Re: Osmium ratios in irons and parent body size(s)

From: E.P. Grondine <epgrondine_at_meteoritecentral.com>
Date: Thu Apr 22 09:50:28 2004
Message-ID: <20020421024959.34015.qmail_at_web11606.mail.yahoo.com>

Many Thanks, Frank -

The next problem is going to be to tie that osmium
data into parent body size(s). Another problem here
seems to be with istopic ratios and their relationship
to core concentrations. Decay ages are probably going
to be significant as well.

All of this is way out of my league, and even if I
came up with anything useful the chances of it going
much beyond this forum are nil. No doubt these osmium
ratios are going to be a key area of work in
meteoritics, and I'm looking forward to what the
experts come up with. Morgan makes a third person
looking at this problem, and his references should
give the total number of experts who have or are
looking at osmium.

My initial question arose from my interest in the
LPBE, and its causes, and its ties to the estimated
total population of potential Earth impacting
asteroids. I'm going to have to go off the meteorite
list in a few days, but I would appreciate it if you
could also forward a separate copy of this information
off list.

good luck on your trip,
and thanks -
ed


--- Frank Prochaska <fprochas_at_premier1.net> wrote:
> Hello!
>
> You may also check out "Handbook of elemental
> Abundances in Meteorites" by
> Brian Mason. There is a section that discusses
> osmium abundances written by
> John Morgan, beginning on page 451. He summarized
> the results of
> measurements on chondrites, achondrites, and irons.
> Table 7 there lists
> figures for 37 different irons. He also references
> the original studies.
>
> This can be a difficult book to find. I am doing a
> final email check as I
> pack my bags to head out on a business trip for the
> week; if I had time, I'd
> post more details. I will be back late Friday. If
> you cannot find or get a
> hold of the book by then, shoot me an email and I
> will send the info when I
> return.
>
> Frank Prochaska
>
>
> -----Original Message-----
> From: meteorite-list-admin_at_meteoritecentral.com
> [mailto:meteorite-list-admin_at_meteoritecentral.com]On
> Behalf Of E.P.
> Grondine
> Sent: Saturday, April 20, 2002 6:46 PM
> To: meteorite-list_at_meteoritecentral.com
> Subject: [meteorite-list] Re: Osmium ratios in irons
> and parent body
> size(s)
>
>
> Great thanks, Bernd - once again your efforts come
> to
> the rescue -
>
> If I understand the results of your database search,
> what it amounts to is that exactly 2 people are
> working on recovering the hard data which will allow
> for the accurate estimate of parent body size(s).
>
> The rest of the work on this problem, and there is
> plenty of it, is "theoretical" at best.
>
> I'm going to have to go off the meteorite list again
> in a few days, so if anyone else has anything to
> offer
> on this problem, please post before then...
>
> ep
>
>
>
> --- Bernd Pauli HD
> <bernd.pauli_at_lehrer1.rz.uni-karlsruhe.de> wrote:
> > E.P. Grondine wrote:
> >
> > > Any idea as to osmium ratios in irons ...?
> >
> > Hi E.P. and List,
> >
> > Here is what I can come up with:
> >
> > CREASER R.A. et al. (1992) Isotopic analysis of Os
> > and Re with negative
> > thermal ion mass spectrometry and application to
> the
> > age and evolution
> > of iron meteorites (Meteoritics 27-3, 1992, A212):
> >
> > Osmium Bennett County Coahuila
> Tocopilla
> >
> >
> > Os 59.610.1 ppm 9.8710.02
> > 1.06210.002
> > 187 Os/188 Os 0.1250315 0.1415817
> 0.16913115
> >
> >
> > Osmium Negrillos Cape York
> C.Diablo
> > Tlacotepec
> >
> > Os 69.410.1
> > 187Os / 188Os 0.1231512 0.1337419 0.13464111
> > 0.1206818
> >
> >
> > ESAT T. et al. (1991) Negative thermal ionization
> > and isotope dilution
> > applied to the determination of Re and Os
> > concentrations and Os isotopic
> > compositions in irons (Meteoritics 26-4, 1991,
> > A333):
> >
> > Osmium Henbury Cape York
> > Kyancutta
> >
> > Os 14.68 ppm 2.497 ppm
> > 0.8746 ppm
> > 187Os / 186Os 1.066 1.118
> > 1.254
> >
> >
> > BROOKS R.R. et al. (1992) Elemental abundance data
> > for the Manitouwabing
> > iron meteorite (Meteoritics 27-2, 1992, 186):
> > Manitouwabing Madoc
> > Osmium 0.73 5g/g 5.19 5g/g
> >
> >
> > Best wishes,
> >
> > Bernd
> >
> > ______________________________________________
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> >
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Received on Sat 20 Apr 2002 10:49:59 PM PDT